diff options
| -rw-r--r-- | arch/x86/include/asm/uprobes.h | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 38 |
2 files changed, 45 insertions, 1 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 9f8210b..e9fd4d5 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -44,9 +44,15 @@ struct arch_uprobe { u16 fixups; const struct uprobe_xol_ops *ops; + union { #ifdef CONFIG_X86_64 - unsigned long rip_rela_target_address; + unsigned long rip_rela_target_address; #endif + struct { + s32 offs; + u8 ilen; + } branch; + }; }; struct arch_uprobe_task { diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index aecc220..c3baeaa 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -461,6 +461,40 @@ static struct uprobe_xol_ops default_xol_ops = { .post_xol = default_post_xol_op, }; +static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + regs->ip += auprobe->branch.ilen + auprobe->branch.offs; + return true; +} + +static struct uprobe_xol_ops branch_xol_ops = { + .emulate = branch_emulate_op, +}; + +/* Returns -ENOSYS if branch_xol_ops doesn't handle this insn */ +static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) +{ + + switch (OPCODE1(insn)) { + case 0xeb: /* jmp 8 */ + case 0xe9: /* jmp 32 */ + break; + default: + return -ENOSYS; + } + + /* has the side-effect of processing the entire instruction */ + insn_get_length(insn); + if (WARN_ON_ONCE(!insn_complete(insn))) + return -ENOEXEC; + + auprobe->branch.ilen = insn->length; + auprobe->branch.offs = insn->immediate.value; + + auprobe->ops = &branch_xol_ops; + return 0; +} + /** * arch_uprobe_analyze_insn - instruction analysis including validity and fixups. * @mm: the probed address space. @@ -478,6 +512,10 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, if (ret) return ret; + ret = branch_setup_xol_ops(auprobe, &insn); + if (ret != -ENOSYS) + return ret; + /* * Figure out which fixups arch_uprobe_post_xol() will need to perform, * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups |